STRUCTURAL CHARACTERIZATION OF DIVALENT MAGNESIUM-DOPED ALPHA-FE2O3

The defect structure of divalent magnesium-doped alpha-Fe2O3 has been examined by Rietveld structure refinement of the X-ray powder diffract ion data. The results show that the Mg2+ ions occupy the vacant inters titial octahedral sites as well as substituting on the two adjacent oc tahedral Fe3+ sites in the corundum-related alpha-Fe2O3 structure, The structure therefore involves a linear cluster of three Mg2+ ions repl acing two Fe3+ ions. Interatomic potential calculations indicate that this is the most energetically favorable defect cluster for the system . (C) 1998 Academic Press.